Invoking the shortcut clause indicates you never wish to discuss a specifically distasteful topic again. It's entymology can be found in a "Simpsons" episode (www.tv.com/the-simpsons/itchy-and-scratchy-land/episode/1392/trivia.html) wherein the family takes a shortcut and a smash-cut brings us back to them, in disarray, with Homer intoning ominously, "Let us never speak of the shortcut again".

You would not use the shortcut clause to avoid talking about something good, only something too horrible or traumatic to want to relive in any manner.